The invention relates to optical networking devices such as cross-connect switches and, more particularly, to cross-connect switches that use micromachined mirror arrays.
The huge bandwidth of optical fibers, in combination with enormous growth of data and voice traffic, has led to a significant amount of recent development activity in the field of optical communications. Advances have occurred in architectures and network components, such as optical switches.
One approach to optical switching involves the use of micro-machined mirror arrays. Prior efforts using this approach, like those of other approaches, tend to have certain shortcomings, such as limited scalability and a relatively low level of integration.
In an aspect of the invention, a structure includes a reference member having a raised portion thereon, a mirror suspended above the raised portion and driving devices disposed on the raised portion to impart rotational motion to the mirror in two axes of direction.
In another aspect of the invention, a method of fabricating micro-mirror structures in a micro-mirror strip of micro-mirror structures includes forming a pyramidal structure from a substrate material and defining electrodes on the pyramidal structure.
In yet another aspect of the invention, a micro-mirror strip assembly includes a frame, an array of two-dimensional deflecting mirrors mounted in the frame and dams disposed between the mirrors to block viscous interaction between each of the two dimensional deflecting mirrors and adjacent ones of the two-dimensional deflecting mirrors in the array.
In still yet another aspect of the invention, a hinge includes a plurality of parallel hinge sections provided by vertical slots therein, the slots and parallel hinge sections being dimensioned to provide vertical and lateral stiffness to and a minimal torsion spring constant for the hinge.
Among the advantages of the present invention are the following. The placement of the electrodes on raised structures on a substrate provides for increased electrostatic force, as well as enhanced instability, thus lowering the required drive voltage and enhancing the deflection angles of the mirrors. The slotted hinge has high torsional flexibility and high stiffness (both vertically and laterally). The dam feature overcomes the undesirable effects of the interaction of the flow of air from adjacent mirrors in a micro-mirror strip assembly.
Other features and advantages of the invention will be apparent from the following detailed description and from the claims.